Multi-component fast-response velocity sensor

Abstract

A system and method for measuring multiple velocity components with a single wire, by alternating current through the wire at a sufficiently high frequency, where the first current allows measurement of a first velocity component, and the second current allows measurement of a second velocity component. The resolution of the measurements can be adjusted by altering the frequency at which the current is alternated.

What is claimed: 
     
       1. A multi-component fast response sensor system, comprising:
 a sensor comprising at least one nano-scale wire configured to be placed in a fluid stream; 
 a first circuit for measuring at least one electrical property associated with the at least one nano-scale wire; 
 a second circuit selected from the group consisting of a switch system or source, the second circuit configured to periodically generate at least a first overheat ratio and a second overheat ratio within the at least one nano-scale wire; 
 a first amplifier configured to generate a first output by increasing a first measurement of the at least one nano-scale wire by a first amount; and 
 a second amplifier configured to generate a second output by increasing a second measurement of the at least one nano-scale wire by a second amount, 
 wherein the outputs are correlated to a first component and a second component of velocity. 
 
     
     
       2. The system according to  claim 1 , further comprising a second wire configured to be placed in the fluid stream, wherein the second wire is capable of measuring a third property of the fluid stream. 
     
     
       3. The system according to  claim 1 , further comprising a second wire configured to be placed in the fluid stream, wherein the second wire is capable of measuring a third component of the velocity. 
     
     
       4. The system according to  claim 1 , wherein the second circuit is configured to alternate current based on a square wave input. 
     
     
       5. The system according to  claim 1 , wherein the second circuit is configured to alternate current at a frequency of between 1 Hz and 500 kHz. 
     
     
       6. The system according to  claim 1 , wherein the at least one nano-scale wire is configured to operate as a hot wire anemometer when a first current is used, and as an elastic filament velocimeter when a second current is used. 
     
     
       7. The system according to  claim 1 , wherein at least one of the first circuit or the second circuit are incorporate into an integrated circuit. 
     
     
       8. The system according to  claim 1 , wherein at least one of the first overheat ratio or second overheat ratio is at least 1. 
     
     
       9. The system according to  claim 1 , wherein at least one of the first overheat ratio or second overheat ratio is at least 1.15. 
     
     
       10. A multi-component fast response sensor, comprising:
 at least one nano-scale wire; 
 an integrated circuit adapted to provide current through the at least one nano-scale wire generating at least a first overheat ratio and a second overheat ratio at a fixed frequency, the integrated circuit comprising;
 a first amplifier configured to generate a first output by increasing a first measurement of the at least one nano-scale wire by a first amount; and 
 a second amplifier configured to generate a second output by increasing a second measurement of the at least one nano-scale wire by a second amount, 
 wherein the outputs are correlated to a first component and a second component of velocity. 
 
 
     
     
       11. The sensor according to  claim 10 , wherein the integrated circuit is further adapted to measure at least one electrical property associated with the at least one nano-scale wire. 
     
     
       12. The sensor according to  claim 10 , wherein the integrated circuit is configured to alternate current at a frequency of between 1 Hz and 500 kHz. 
     
     
       13. The sensor according to  claim 10 , wherein the integrated circuit further comprises a limiter. 
     
     
       14. A method of measuring multiple velocity components with a single sensor, comprising the steps of:
 providing a nano-scale wire configured to be placed in a fluid stream; 
 providing a circuit that is configured to periodically generate at least a first and a second overheat ratio in the nano-scale wire; 
 generating the first overheat ratio in the wire; 
 generating a first measurement by measuring at least one electrical property associated with the wire; 
 generating the second overheat ratio in the wire; 
 generating a second measurement by measuring at least one electrical property associated with the wire; 
 correlating the measurements with a first component of velocity and a second component of velocity. 
 
     
     
       15. The method according to  claim 14 , further comprising generating a square wave input for controlling the frequency at which the first and second overheat ratios are generated. 
     
     
       16. The method according to  claim 15  wherein the at least one of the first overheat ratio or second overheat ratio is at least 1.15. 
     
     
       17. The method according to  claim 14 , wherein generating at least a first and second overheat ratio comprises switching a current at a frequency of between 1 Hz and 500 kHz. 
     
     
       18. The method according to  claim 14  wherein the at least one of the first overheat ratio or second overheat ratio is at least 1. 
     
     
       19. The method according to  claim 14 , further comprising correcting for attenuation of the first and second outputs based on the frequency at which the current is switched. 
     
     
       20. The method according to  claim 14 , wherein the circuit comprises a closed-loop feedback system configured to adjust at least one of the first or second current.